The pulmonary toxicity of environmental and occupational noxious particulates is often enhanced by impairment of normal clearance mechanisms prolonging their residence time in the lung. Clearance mechanisms vary strongly between individuals, resulting in a highly variable sensitivity to such contaminants. Up to this time, detailed studies of clearance mechanisms and particulate accumulation in human subjects has not been possible because of the excessive radiation associated with existing techniques. The recently developed technique of magnetopneumography (MPG) now offers a non-invasive, purely passive means to conduct such studies. It also offers the potential for routine screening of individuals to measure clearance times and hence classify people relative to their susceptibility to lung damage in various environmental conditions. Additionally, MPG may be used to monitor dust accumulation for people in environments known to be hazardous over time; when critical levels of particulate accumulations have been reached, those individuals may be removed as required from the environment in question. An example of this would be the monitoring of coal dust accumulation in coal miners. The first generation of superconducting magnetometers constructed by S.H.E. Corporation and used in the pioneering MPG work have certain serious limitations which make widespread clinical research impractical. We are here proposing to identify the sources of those limitations and minimize or eliminate them. This will be done in consultation with the medical research group which conducted most of the pioneering research. The primary Phase I effort will study the instrument drift sources (flux motion in superconducting materials, magnetic relaxation effects, etc.) resulting from exposure to the dc fields required by the technique. Various new pickup coil arrays will be evaluated to obtain improved sensitivity deep in the lungs and to reduce measurement time. Upon resolution of these two issues, a preliminary design of a complete instrument suitable for extensive clinical studies will be prepared. In Phase II, that prototype instrument will be produced and made available for clinical studies. Successful completion of these studies will lead to our commercialization and production of an MPG instrument package.